MARG HELGENBERGERmakes her final appearance as Catherine Willows in a new episode of “CSI: Crime Scene Investigation” at 9 p.m. on CBS.

SERIES

Whitney: Roxanne (Rhea Seehorn) hires Whitney (Whitney Cummings) as her office assistant, but the job description includes more than typing and filing. There’s also a bit of spying. Kathy Griffin, Dan O’Brien and Maulik Pancholy also star in this new episode (8 p.m. NBC).American Idol: Hopefuls in Aspen perform (8 p.m. Fox).Nature: Some 1,700 brown bears take up residence in the Tongass National Forest in southeastern Alaska in the new episode “Fortress of the Bears” (8 p.m. KOCE).Criminal Minds: In the series’ 150th episode, the team is in Houston, where a serial rapist called the Piano Man has resurfaced and is targeting his past victims (9 p.m. CBS).Touch: Kiefer Sutherland stars in this new drama about a widower and single father haunted by an inability to connect to his mute 11-year-old son (David Mazouz), until he learns the boy possesses a gift that enables him to see things no one else can (9 p.m. Fox).NOVA: The new episode “Mystery of a Masterpiece” follows experts who approach “art mysteries” such as thefts and forgeries as if they were conventional crime scenes (9 p.m. KOCE).Royal Pains: Hank (Mark Feuerstein) has trouble trusting Divya (Reshma Shetty) after her prescription error, but he has to work with her to diagnose the illness that’s hit the members of a rising rock band in this new episode (10 p.m. USA).

SPECIALS

When Vacations Go Bust: This new special showcases mishaps that happen to folks away from home (10 p.m. Travel).

MOVIES

Tabloid: Veteran documentarian Errol Morris tells the stranger-than-fiction tale of a former beauty queen accused of kidnapping a Mormon missionary in England and holding him captive as a sex slave (6:30 p.m. Showtime).